Bisbiphenylacylphosphine oxide and preparation method therefore

ABSTRACT

A bisbiphenylacylphosphine oxide of formula (I) and its preparation method are provided. The formula of —Ar— is 
                         
First, 10-chloro-9,10-dihydro-9-oxa-10-phosphaphenanthrene (CDOP) is prepared by using 2-phenylphenol, and then is esterified to synthesize 6-methoxy-(6H)-dibenz[c,e][1,2]oxa-phosphorin (MDOP). Next, acid chloride compounds are added for performing the Arbuzov reaction to synthesize bisbiphenylacylphosphine oxide. CDOP is hydrolyzed to be derived into 9,10-dihydro-9-oxa-10-phosphaphen-anthrene-10-oxide (DOPO), and then DOPO reacts with arylaldehyde to form secondary alcohol. Therefore, bisbiphenylacylphosphine oxide is prepared by using secondary alcohol under oxidation. Also, under a coupling reaction, DOPO reacts with the acid chloride compounds by using a Lewis acid as a catalyst to prepare bisbiphenylacylphosphine oxide.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a divisional of copending application Ser. No.11/337,441, filed Jan. 24, 2006, the entire disclosure of which isincorporated herein by reference.

BACKGROUND

1. Field of Invention

The invention relates to a photoinitiator and a preparation methodthereof and in particular to a bisbiphenylacylphosphine oxide and itspreparation method.

2. Related Art

A photoinitiator is a spectacular compound that can absorb a specificwavelength of photo energy to release free radicals by a cleavage or βcleavage. Therefore it can be used as an initiator for a monomer chainreaction. Most photoinitiators have the properties of low price, goodstability, no toxicity, no colorizing, easy to make, long life span freeradical and good light absorption rate. Recently, the demand for itsapplication has driven the development of low energy and long wavelengthlight initiators, with most of the initiators consisting of a carbonylchromophoric group. In a light wavelength range of 300 nm to 400 nm andbased on the Norrish Type I, a photoinitiator of biphenylacryphosphineoxide can directly release free radicals without the assist of asensitizer, so that it can be directly used for polymerizing acrylics.

Most of the acryphosphine oxides such as those disclosed in U.S. Pat.Nos. 5,407,969, 5,008,426 and European patent 413657 belong to analiphatic group, a phenyl group or a monophenylacryphosphine oxide andhave remarkable effects in practice. However, the light initiatorcompound should have greater equivalent to make the polymerization moreefficient. Thus, how to develop a high equivalent compound for a lightinitiator has become an important topic in the field.

SUMMARY

One object of the invention is to provide a bisbiphenylacylphosphineoxide and a preparation method therefore.

According to the invention, a bisbiphenylacylphosphine oxide can berepresented by the following structural formula (I):

wherein —Ar— is a phenyl group, and the phenyl group can be

According to the invention, an embodiment of a method for preparing abisbiphenylacylphosphine oxide is provided where thebisbiphenylacylphosphine oxide has the structural formula (I) and —Ar—is a phenyl group. The method includes the steps of: heating an excessphosphorus trichloride and a 2-phenylphenol with a catalyst to form a10-chloro-9,10-dihydro-9-oxa-10-phosphaphenanthrene (CDOP) where theCDOP is represented by the following structural formula (II); removingthe remaining phosphorus trichloride; esterifying the CDOP to become a6-methoxy-(6H)-dibenz[c,e][1,2]oxa-phosphorin (MDOP) where the MDOP isrepresented by the following structural formula (III); and conducting anArbuzov reaction with the MDOP and a acid chloride compound to form thebisbiphenylacylphosphine oxide, which has the following structuralformula (I).

According to the invention, another embodiment of a method for preparinga bisbiphenylacylphosphine oxide is provided where thebisbiphenylacylphosphine oxide has the structural formula (I) and —Ar—is a phenyl group. The method includes the steps of: heating an excessphosphorus trichloride and a 2-phenylphenol with a catalyst to form a10-chloro-9,10-dihydro-9-oxa-10-phosphaphenanthrene (CDOP) where theCDOP is represented by the following structural formula (II); removingthe remaining phosphorus trichloride; hydrolyzing the CDOP to form a9,10-dihydro-9-oxa-10-phosphaphen-anthrene-10-oxide (DOPO) where theDOPO is represented by the following structural formula (IV); conductingan addition and oxidization reaction or a coupling reaction with theDOPO to form the bisbiphenylacylphosphine oxide, which has thestructural formula (I).

The DOPO can conduct an addition reaction with an arylaldehyde to form asecondary alcohol, followed by mixing the secondary alcohol with anoxidant to form the bisbiphenylacylphosphine oxide, which has thestructural formula (I).

Or, the DOPO can conduct a coupling reaction with an acid chloridecompound and a catalyst to form the bisbiphenylacylphosphine oxide,which has the structural formula (I).

DETAILED DESCRIPTION

First, add an excess phosphorus trichloride (PCl₃), a 2-phenylphenol anda tiny amount of catalyst such as zinc chloride (ZnCl₂) into a reactor;then conduct a first step of an esterifying reaction by heating attemperature of 30 to 80° C. and under normal pressure for one hour;next, raise the temperature to 150 to 200° C. for 6 hours to conduct thesecond step of an thermo-dynamic trans-esterification and intramolecularcyclization; use a ³¹P nuclear magnetic resonance (³¹PNMR) to measurethe end point of the reaction; and after the reaction is completed,recycle the remaining phosphorus trichloride; then an intermediate10-chloro-9,10-dihydro-9-oxa-10-phosphaphenanthrene (hereinafter referto CDOP) is obtained. This reaction is shown equation (1),

where

is the structural formula of the 2-phenylphenol, and

is the structural formula of the CDOP.

Next, add a methanol (CH₃OH) and a triethylamine ((C₂H₅)₃N) to the CDOPin toluene (C₇H₈) to conduct an esterifying reaction; then distill thesolution to produce a 6-methoxy-(6H)-dibenz[c,e][1,2]oxa-phosphorin(hereinafter referred to as MDOP); and mix the MDOP and an acid chloridecompound to conduct an Arbuzov reaction at a temperature of 60 to 140°C. for synthesizing the bisbiphenylacylphosphine oxide. This reaction isshown equation (2),

where

is the structural formula of the MDOP,

is the structural formula of the acid chloride compound, and

is the structural formula of the bisbiphenylacylphosphine oxide. Inthese structural formulas, —Ar— is the phenyl group, which can be a

When —Ar— is

the bisbiphenylacylphosphine oxide will be1,2-bis(6-(6H)-dibenz[c,e][1,2]oxaphosphorin-6-oxide) benzoate(hereinafter referred to as PCPO); when —Ar— is

the bisbiphenylacylphosphine oxide will be1,3-bis(6-(6H)-dibenz[c,e][1,2]oxaphosphorin-6-oxide) benzoate(hereinafter referred to as ICPO); and when —Ar— is

the bisbiphenylacylphosphine oxide will be1,4-bis(6-(6H)-dibenz[c,e][1,2]oxaphosphorin-6-oxide) benzoate(hereinafter referred to as TCPO).

Additionally, the CDOP can be hydrolyzed to9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (hereinafter referredto as DOPO), followed by conducting an addition reaction with anarylaldehyde for obtaining a secondary alcohol; next this secondaryalcohol is oxidized to a bisbiphenylacylphosphine oxide. The reaction isshown equation (3),

where

is the structural formula of the DOPO,

is the structural formula of the arylaldehyde, and

is the structural formula of the secondary alcohol. When —Ar— is

the secondary alcohol is1,2-bis(6-(6H)-dibenz[c,e][1,2]oxaphosphorin-6-oxide)benzyl alcohol(hereinafter referred to as PHCPO); when —Ar— is

the secondary alcohol is1,3-bis(6-(6H)-dibenz[c,e][1,2]oxaphosphorin-6-oxide)benzyl alcohol(hereinafter referred to as IHCPO); and when —Ar— is

the secondary alcohol is1,4-bis(6-(6H)-dibenz[c,e][1,2]oxaphosphorin-6-oxide)benzyl alcohol(hereinafter referred to as THCPO).

Also, a Lewis acid can be used as a catalyst for the DOPO and the acidchloride compound to conduct a coupling reaction to produce abisbiphenylacylphosphine oxide, which is shown equation (4).

EMBODIMENT 1

1. Synthesis of CDOP

Add one mole of 2-phenylphenol (about 170 g), 1.1 moles of phosphorustrichloride (about 151 g) and 0.01 moles of zinc chloride (about 1.36 g)into a reactor. Then install a dropping bottle between the reactor andthe condenser; the dropping bottle has a pressure balance tube and acontrolling valve. The condenser is maintained at about 0° C. and isconnected to a ventilated tube at the top. Then, the ventilated tubecommunicates to a neutralization sink by a dry tube. Raise the solutionto about 30° C. for initiate the reacting. The temperature will maintainat 60° C. to 80° C. during the reaction. After an hour of reaction, thehydrochloric acid vapor producing rate by the reaction between thephosphorus trichloride and the 2-phenylphenol will slow down.

In the second step of thermo-dynamic trans-esterification andintramolecular cyclization. Here, the temperature is raised and thephosphorus trichloride is continually distilled out and then condensedin the dropping bottle. When the temperature is raised to about 110° C.,start to slowly drop back the phosphorus trichloride from the droppingbottle. Then, continually raise the temperature to about 180° C. After 6hours, when the hydrochloric acid vapor is barely being produced, thereaction can probably be finished. Here, sample the solution to proceedwith the ³¹PNMR test to accurately determine the reaction end point. TheCDOP can be obtained by decompressed distilling the remained solution,and the phosphorus trichloride can be recycled during the decompresseddistilling process.

Next, introduce 500 milliliter toluene into the reactor where the CDOPis. After stirring and still for a moment; a sticky polyphosphateprecipitates and adheres to the wall of the reactor. After filtering themixture and distilling out the toluene, a 233 g of CDOP can be obtained.The yield is approximately 100%.

2. Synthesis of MDOP

After the phosphonating reaction, add one mole of CDOP with 500milliliter toluene into the reactor. Then drop a mixture solution withabout one mole of methanol and one mole of triethylamine into thereactor. Stir the solution while raising the temperature to 50° C. Aftercontinuously dropping the mixture solution into the reactor for an hour,keep stirring it for another hour. Next, the produced triethylaminehydrichloride ((C₂H₅)₃N.HCl) is precipitated by giving the reactor anice bath. After filtering the precipitated triethylamine hydrochloride,recycle the toluene solvent by distillation. Then, the MDOP can beobtained by distillation under a condition of decompressing (about 1mmHg) and at a temperature of 140 to 150° C. The yield is about 92%.

3. Synthesis of PCPO

Add 0.2 moles of MDOP (about 46 g) and 0.1 moles of phthaloyl chloride(about 20.3 g) into the reactor and heat them for 2 hours under atemperature of 120° C. When the reaction is completed, decompress it(about 20 mmHg to 30 mmHg) for 5 minutes. After that, white solidpowders can be obtained. After returning the products to the roomtemperature, use toluene to rinse out the un-reacted reactants. Then,the toluene contained products are further filtered and dried to get thePCPO. The yield is about 45%.

4. Synthesis of ICPO

Add 0.2 moles of MDOP (about 46 g) and 0.1 moles of isophthaloylchloride (about 20.3 g) into the reactor and heat them for 2 hours undera temperature of 120° C. When the reaction is completed, decompress it(about 20 mmHg to 30 mmHg) for 5 minutes. After that, white solidpowders can be obtained. After returning the products to roomtemperature, use toluene to rinse out the un-reacted reactants. Then,the toluene contained products are further filtered and dried to get theICPO. The yield is about 63%.

5. Synthesis of TCPO

Add 0.2 moles of MDOP (about 46 g) and 0.1 moles of terephthaloylchloride (about 20.3 g) into the reactor and heat them for 2 hours undera temperature of 120° C. When the reaction is completed, decompress it(about 20 mmHg to 30 mmHg) for 5 minutes. After that, white solidpowders can be obtained. After returning the products to roomtemperature, use toluene to rinse out the un-reacted reactants. Then,the toluene contained products are further filtered and dried to get theTCPO. The yield is about 85%.

EMBODIMENT 2

1. Synthesis of DOPO

Add one mole of CDOP with a 500 milliliter toluene into a reactor. Addone mole of water (about 18 g) by dropping for about one hour. Thecondenser uses water for cooling. The hydrochloric acid vapor is lead tothe neutralization sink by going through the ventilated tube whichconnects to the top of the condenser. When the dropping is finished,reflux it for an hour. Then introduce the nitrogen into the solution,reflux it for another 2 hours for blowing out the remaining hydrochloricacid vapor. After return to room temperature, white solid DOPOprecipitates. The yield is about 95% after filtering and dying.

2. Synthesis of PHCPO, IHCPO and THCPO

Dissolve 0.1 moles of DOPO (about 21.6 g) with 0.05 moles of1,2-phthalaldehyde or 1,3-phthalaldehyde, or 1,4-phthalaldehyde (eachabout 6.7 g) respectively in an about 50 milliliter toluene for reflux 6hours. After returning the solution to room temperature, white solidpowders precipitate. The toluene can be further used to rinse out theun-reacted reactants. Next, they are filtered and dried and then a 28%yield PHCPO, a 41% IHCPO and an 85% THCPO can be respectively obtained.

3. Oxidation Reaction for PHCPO, IHCPO and THCPO

Dissolve 0.005 moles of PHCPO or IHCPO or THCPO (each about 2.83 g) in a20 milliliter dimethyl sulfoxide (DMSO) respectively, and use 0.8 gmanganese dioxide (MnO₂) to be the oxidant for reacting 24 hours atabout 70° C. Then after returning the solution to room temperature andquench by water, white solid powders precipitates.

About 1.3 g of oxalyl chloride ((ClCO)₂) can be used as the oxidant forreacting 24 hours at room temperature. When water is used to end thereaction, white solid powders precipitates.

In the oxidization step with manganese dioxide, the PHCPO has a PCPOyield of 68%, the IHCPO has an ICPO yield of 71%, and the THCPO has aTCPO yield of 82% after drying. On the other hand, in the oxidizationstep with the oxalyl chloride, the PHCPO has a PCPO yield of 47%, theIHCPO has an ICPO yield of 61%, and the THCPO has a TCPO yield of 72%after drying.

EMBODIMENT 3

Add 0.2 moles of DOPO (about 43.2 g) with 0.1 moles of phthaloylchloride or isophthaloyl chloride or terephthaloyl chloride (each about20.3 g) respectively into a reactor. Then add 0.3 g aluminiumtrichloride as a catalyst and about 50 milliliter toluene into thereactor with reflux 4 hours. After the reaction completes and thesolution is returned to room temperature, white solid powdersprecipitate. The toluene can be further used to rinse out the un-reactedreactants after filtering. After they are dried, a 25% yield PCPO, a 45%ICPO and a 76% TCPO can be respectively obtained.

Identify the synthesized compounds and intermediates with the infraredspectroscopy (IR). The main peaks located around 900 cm⁻¹-1050 cm⁻¹,1645 cm⁻¹, and 1230 cm⁻¹ are identified as P—O bond, C═O bond, and P═Obond, respectively. The O—H bond spectrums of IHCPO, PHCPO, and THCPOlocate around 3230 cm⁻¹. By using the ¹H NMR to identify the synthesizedcompounds and intermediates, the chemical shift of a methoxy group ofthe MDOP is 3.5 ppm and exhibits two peaks because of the couplingeffect of the phosphorous, this coupling constant is about 10 Hz. Thechemical shift of the P—H bond of the DOPO is around 8.0 ppm, and it hasa coupling constant of about 600 Hz. Except for the absorption of thehydrogen groups on the benzene ring of the PHCPO, IHCPO and THCPO, thechemical shift of the hydrogen on the benzyl group is between 5.1 ppmand 5.5 ppm. The chemical shifts of the hydrogen groups on the benzenering of the PCPO, ICPO and TCPO are between 7.4 ppm and 8.4 ppm.Furthermore, by using a mass spectrometry (MS) to identify thesynthesized compounds and intermediates, the molecular weight for PCPO,ICPO and TCPO are determined as 562. And the base peak is P—C bondcleavage, identifies 347 and 215 fragment ion peak. The molecular weightof the PHCPO, IHCPO and THCPO are 566 and the base peak of the C—P bondcleavage, identifies fragment ion peak 351. In addition, phosphine oxidehas its own specific absorption positions. Therefore a ³¹PNMR can beused to identify the structure of the compound. Please refer to thefollowing table 1, showing the structural formula of compounds and therelative signal absorption positions.

TABLE 1 Relative signal Compound Structural formulas absorption positionCDOP

134.1 ppm MDOP

129.2 ppm PCPO

21.8 ppm ICPO

22.1 ppm TCPO

22.3 ppm DOPO

15.4 ppm PHCPO

31.2 ppm IHCPO

31.4 ppm THCPO

31.6 ppm

1. A preparation method for bisbiphenylacylphosphine oxide, thebisbiphenylacylphosphine oxide represented by the following structuralformula (I),

wherein —Ar— is a phenyl group, the method comprising: heating an excessphosphorus trichloride and a 2-phenylphenol with at least one catalystto form a 10-chloro-9,10-dihydro-9-oxa-10-phosphaphenanthrene (CDOP)wherein the CDOP is represented by the following structural formula(II);

removing the remaining phosphorus trichloride; hydrolyzing the CDOP toform a 9,10-dihydro-9-oxa-10-phosphaphen-anthrene-10-oxide (DOPO)wherein the DOPO is represented by the following structural formula(IV); and

conducting one of an addition and oxidization reaction and a couplingreaction with the DOPO to form the bisbiphenylacylphosphine oxide whichhas the structural formula (I).
 2. The preparation method of claim 1wherein the step of conducting one of an addition and oxidizationreaction and a coupling reaction with the DOPO includes: conducting anaddition reaction with the DOPO and at least one arylaldehyde to form asecondary alcohol; and mixing the secondary alcohol with at least oneoxidant to form the bisbiphenylacylphosphine oxide which has thestructural formula (I).
 3. The preparation method of claim 2 wherein thestep of oxidization reaction proceeds in an organic solvent.
 4. Thepreparation method of claim 3 wherein the organic solvent is dimethylsulfoxide.
 5. The preparation method of claim 2 wherein the oxidant isselected from the group consisting of an oxalyl chloride and a manganesedioxide.
 6. The preparation method of claim 1 wherein the step ofconducting one of an addition and oxidization reaction and a couplingreaction with the DOPO includes: conducting the coupling reaction withthe DOPO, at least one acid chloride compound and at least one catalystto form the bisbiphenylacylphosphine oxide which has the structuralformula (I).
 7. The preparation method of claim 6 wherein the catalystis a Lewis acid.
 8. The preparation method of claim 7 wherein the Lewisacid is aluminium trichloride.
 9. The preparation method of claim 1wherein the catalyst is zinc chloride.
 10. The preparation method ofclaim 1 wherein a mole ratio of the phosphorus trichloride to the2-phenylphenol in the step of heating an excess phosphorus trichlorideand a 2-phenylphenol is between 1.1 and 1.2.
 11. The preparation methodof claim 1 wherein the step of heating an excess phosphorus trichlorideand a 2-phenylphenol proceeds under a temperature range of 30° C. to200° C.